Question

Which of the following statements about adaptive immunity are correct ? A. Adaptive immunity includes physical and chemical barriers to infection.
B. Adaptive immunity evolves in real time in response to infection.
C. Adaptive immunity response is highly diverse in specificity.
D. Major components of adaptive immunity are phagocytes.
E. Adaptive immune response has immunologic memory.
Choose the correct answer from the options given below :

• A. \(B, C, E\) only
• B. \(A, B\) only
• C. \(C, D, E\) only
• D. \(D, E\) only

Hint:

Remember: \[ \text{Innate immunity} \rightarrow \text{Immediate, non-specific} \] \[ \text{Adaptive immunity} \rightarrow \text{Specific with memory} \] Key features of adaptive immunity:
• Specificity
• Diversity
• Memory

Answer 1

The Correct Option is A

Concept: Adaptive immunity is a specialized defense mechanism that develops in response to specific pathogens. Important features of adaptive immunity include:
• Antigen specificity
• Immunological memory
• Diversity of antigen recognition
• Ability to improve upon repeated exposure The major cells involved are:
• B lymphocytes
• T lymphocytes

Step 1: Evaluating statement A. Statement A: \[ \text{Adaptive immunity includes physical and chemical barriers} \] This is incorrect. Physical and chemical barriers such as:
• Skin
• Mucus
• Gastric acid belong to: \[ \text{Innate immunity} \] Thus: \[ \boxed{A \text{ is incorrect}} \]

Step 2: Evaluating statement B. Statement B: \[ \text{Adaptive immunity evolves in response to infection} \] This is correct because adaptive immunity develops after exposure to antigens. Thus: \[ \boxed{B \text{ is correct}} \]

Step 3: Evaluating statement C. Statement C: \[ \text{Adaptive immune response is highly diverse in specificity} \] This is correct. Adaptive immunity can recognize a vast number of different antigens through diverse antigen receptors. Thus: \[ \boxed{C \text{ is correct}} \]

Step 4: Evaluating statement D. Statement D: \[ \text{Major components of adaptive immunity are phagocytes} \] This is incorrect. Phagocytes such as macrophages and neutrophils mainly belong to: \[ \text{Innate immunity} \] Adaptive immunity mainly involves: \[ \text{B and T lymphocytes} \] Thus: \[ \boxed{D \text{ is incorrect}} \]

Step 5: Evaluating statement E. Statement E: \[ \text{Adaptive immune response has immunologic memory} \] This is correct. Memory cells enable faster and stronger responses upon re-exposure to the same antigen. Thus: \[ \boxed{E \text{ is correct}} \] Therefore, the correct statements are: \[ \boxed{B, C, E} \] Hence, the correct answer is: \[ \boxed{(A)\ B, C, E \text{ only}} \]